The last company I worked for still had customers they were dragging forward to get upgrades from coax connexted green screen terminals to modern network thin clients. It wasnt on DOS, but very old unix OS, tape drives for backups, parallel for printers, serial for scanners. No USB. Lovely troubleshooting when you were dealing with 30+ year old hardware setups. There was only one company that would even servicenthe green screens if they failed, and you couldn't buy them anymore.